1. Field of the Invention
This invention relates to diagnostic instruments and more particularly to a thermoelectric instrument for applying heat and cold to small selected portions of the patient's body. The device finds particular application as a dental pulp tester.
2. Description of the Prior Art
A diagnostic procedure often employed in dentistry is that of thermal pulp testing wherein the temperature of a tooth is either raised or lowered by the application of heat or cold. Conventionally used pulp testing procudures, such as those described in an article entitled "Thermal Pulp Testing" commencing on page 58 of the May/June, 1978 issue of General Dentistry magazine, are often inconvenient, time consuming, messy and potentially harmful to the patient. As a consequence, several attempts have been made in the past to design instruments specifically adapted for applying heat or cold to a localized area of the body such as a tooth surface. Examples of such instruments are shown in the following patents: Eidus U.S. Pat. No. 3,274,995 issued Sept. 27, 1966; Scher U.S. Pat. No. 3,533,397 issued Oct. 13, 1970; Crump et al U.S. Pat. No. 3,575,176 issued Apr. 20, 1971; Frank et al U..S. Pat. No. 3,618,590 issued Nov. 9, 1971; and Foti U.S. Pat. No. 4,143,649 issued Mar. 13, 1979.
A major difficulty in the prior art, especially with respect to those devices employing mechanisms utilizing the Peltier effect, has been the efficient dissipation of excess heat build-up. The complex and voluminous heat exchange systems and heat sinks thus far employed in an attempt to solve this problem has limited acceptance of such devices.